I am having a problem when using the Import Wizard to import users and groups. I marked it to import favorite folders for selected users and all groups and users. Well, the user favorites folder keeps failing with "The owner of this Favorite Folder was not found" and the groups are not associating the users in the new system under the same alias with the groups.
Old system I am using AD NTLM. New system I am using AD Kerberos.
for importing AD users, you have to first configure the AD authentication piece on the new server. I don't think you can import the users over until the AD is setup.
Alternatively, you can convert your users accounts to Enterprise user accounts before importing them over. Once they are in the new system, you can setup the AD authentication and groups and any existing accounts with the same name should get AD aliases assigned to them.
I've never tested going from NTLM to Kerberos users but I don't think that should be a factor.
Hope this helps,